[K3PZN-List] Antenna Problems

[Curt Milton]

Ray

A G5RV antenna is designed to emphasize its radiation conditions over many bands - not its VSWR.  


It is very difficult to make an antenna with a low VSWR on every band at the same time.  


For a full-sized G5RV - its VSWR is best on 20m - but even here it may not get close to a 1:1 VSWR.  


This website has a plot of VSWR vs frequency.  Note it will vary some versus height and installation particulars.  


http://www.w8ji.com/g5rv_facts.htm

Looking at this curve with my own eyes - with some kind of antenna tuner - it will be most useful on 20, 40 and 80 meters.  On the lower bands the high VSWR is less of a problem because coax loss is lower.  To a ham in 'olden times' these were the 3 most important bands.  The antenna might also be useful on 12m - but it depends where the resonance lands.  


I suggest evaluating your antenna first on 20m - to see if you can find a place where VSWR dips some.  If you are using a normal VSWR meter I would check VSWR about every 50 kHz on 20m.  If its VSWR does not change and is very high, I might suspect you would have a connection problem.  


Finding those dips on 40 and 80m may be a little tougher, so this is why I suggest evaluating 20m first.  Keep in mind your antennas behavior will be similar but not at exactly same frequencies to this one.  


I agree it is a 'confusing antenna' from its VSWR response.  But it should be a very good antenna on 20m, and useful on 40 and 80m.  Some day when you want to add 15 and 10m, these are much smaller dipoles and these 2 dipoles can be feed with the same coax feed.  I do use one ladder line fed antenna here that uses no coax - and it is useful.  


A bit complex - here is another description of this antenna:  http://www.qsl.net/aa3px/g5rv.htm -- yes this write up is by G5RV himself.  


Meanwhile do not give up on the G5RV antenna - but do figure out if it has a changing VSWR vs. frequency.  I emailed the gang since I did not include an attachment, and that they would not type the same info to you.  I am good in phone book so call me if you need to talk.  


Curt





________________________________
 From: Ray Wright <razor42 at hughes.net>
To: Carroll County Amateur Radio Club <k3pzn-list at mailman.qth.net> 
Sent: Saturday, March 3, 2012 7:50 AM
Subject: Re: [K3PZN-List] Antenna Problems
 
Sorry changed the subject to antenna problem.    Sorry for the additional 
spam

----- Original Message ----- 
From: "Ray Wright" <razor42 at hughes.net>
To: "Carroll County Amateur Radio Club" <k3pzn-list at mailman.qth.net>
Sent: Friday, March 02, 2012 9:48 PM
Subject: Re: [K3PZN-List] Repeater Work Cancelled


> hello everyone Ray KB3VWK
>
> Well Kerri Kb3wav and I got a G5RV antenna had got some LMR 400 from Mike
> hooked it all up.  I have the antenna at 60ft on both ends and 40ft at the
> feed point.  But I am still getting high swr's  Any help on correcting 
> this
> problem would be greatly appreciated.   I am going to work on the ground
> tmw.  But would like to know if anyone in the club has a g5rv and how do 
> you
> have it set up.   It is feed with ladder line and the instructions call 
> for
> antenna tunner I am using an ldg 11pro.
>
>
> regards ray
>
>
> ----- Original Message ----- 
> From: "Wayne" <M.Wayne.Wilson at comcast.net>
> To: "'Carroll County Amateur Radio Club'" <k3pzn-list at mailman.qth.net>
> Sent: Friday, February 17, 2012 8:52 PM
> Subject: Re: [K3PZN-List] Repeater Work Cancelled
>
>
>>
>>
>>
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